1. Field
Apparatuses and methods consistent with the exemplary embodiments generally relate to an optical pick-up apparatus, and more particularly, to an optical pick-up apparatus using a diffracted beam.
2. Description of the Related Art
An optical pick-up apparatus is an apparatus recording information on an optical recording medium or reproducing information recorded on an optical recording medium. The optical recording media include a CD (Compact Disc) using a beam with a wavelength of approximately 780 nm, a DVD (Digital Versatile Disc) using a beam with a wavelength of approximately 660 nm and a BD (Blu-ray Disc) using a beam with a wavelength of approximately 405 nm and the optical recording media have different structures from each other. Recently, a compatible optical pick-up apparatus which can be used with various types of optical recording media is being developed.
One of the approaches to develop such a compatible optical pick-up apparatus is to use a plurality of objective lenses. In other words, the optical pick-up apparatus includes an objective lens for each of a CD, a DVD, and a BD. However, with this approach minimization of the optical pick-up apparatus cannot be achieved.
Another approach to develop a compatible optical pick-up apparatus is to use a diffraction element in an optical system of the optical pick-up apparatus. Such a diffraction element may correct an aberration generated by a structure of various kinds of an optical recording medium, various beams with different wavelengths and temperature changes. In this case, minimization of the optical pick-up apparatus is possible as one objective lens is used instead of the plurality of objective lenses.
For the optical pick-up apparatus using the diffraction element, only a diffracted beam of a specific order among diffracted beams generated by a diffraction element is used for recording and reproducing information. However, there is a concern that diffracted beams of other orders not used for recording and reproducing information may generate noise on information that will be recorded or reproduced. Therefore, it is necessary to prevent noise generated by a diffracted beam of other orders not used for recording and reproducing information.